The problem came to national attention in recent days via text messages warning of the affected fruits, but authorities in Sichuan province knew as early as September 23, the Beijing News said.

The report said authorities in the city of Guangyuan were told of the problem two days after it was first discovered in tens of thousands of trees in the area.

However, it was not publicly announced until last week, it added.

“Word of the problem affected sales of mandarin oranges nationwide, but Sichuan’s provincial agriculture authorities did not hold a news conference on the subject for a full month afterward,” it said.

The report said local Sichuan authorities took some measures to control the problem, but numerous Chinese media reports have said the affected fruits continued to be sold across the country for weeks afterward.